Can somebody please explain the cell mediated response and humeral response? Am major stuck as to the difference in sequence!?? Thanks

Okay so i get the bit where the pathogen is engulfed by the cell through phagocyctosis, and is then displayed on itself as a non-self antigen, and then..... yeah thats when i don't get it! Please help:(

4 Answers

3 votes

Cell-mediated response takes place when cells are invaded by the pathogen. This involves T lympocytes. T helper cells will bind to the antigens presented by the invaded cell or phagocyte. They will then activate T lymphocytes to divide by mitosis. T lymphocytes will form memory cells that will provide long lasting immunity (they remember the antigens and will quickly respond if the pathogen carrying this antigen enters the body again). T lymphocytes will also kill invaded cells by making holes in their cell membranes, and they will stimulate both B lymphocytes and phagocytes.

Humoral response takes place when pathogens are in the blood and tissue fluids. B lymphocytes will take up antigens, and present them. A T helper cell will then bind to the antigen, and activate the B lymphocyte. The B lymphocyte will then multiply by mitosis. It will form plasma cells, which produce antibodies which kill pathogens. It will also form memory cells which will provide long lasting immunity.

The humoral response (or antibody-mediated response) involves B cells that recognize antigens or pathogens that are circulating in the lymph or blood (“humor” is a medieval term for body fluid). The response follows this chain of events:

Antigens bind to B cells.

Interleukins or helper T cells costimulate B cells. In most cases, both an antigen and a costimulator are required to activate a B cell and initiate B cell proliferation.

B cells proliferate and produce plasma cells. The plasma cells bear antibodies with the identical antigen specificity as the antigen receptors of the activated B cells. The antibodies are released and circulate through the body, binding to antigens.

B cells produce memory cells. Memory cells provide future immunity.

The cell-mediated response involves mostly T cells and responds to any cell that displays aberrant MHC markers, including cells invaded by pathogens, tumor cells, or transplanted cells. The following chain of events describes this immune response: